Closure for containers



Dec. 5, 1961 GABUZDA 3,011,690

CLOSURE FOR CONTAINERS Filed Dec. 12, 1957 4 I'll!!! INVENTOR.

. GABUZDA United States Patent 3,011,690 CLOSURE FOR CONTAINERS George E. Gabuzda, Wilmington, Del., assiguor to Atlas Chemical Industries, Inc., a corporation of Delaware Filed Dec. 12, 1957, Ser. No. 702,384 1 Claim. (Cl. 229-62) This invention relates to a closure for containers made of flexible waterproof material and to methods of providing a seal for such containers, which seal is impervious to water pressure for prolonged periods of time.

More specifically this invention is concerned with providing bag closures for explosive material which will withstand considerable hydrostatic pressure for extended periods of time without permitting the contents of the bag to become wet with water.

It is necessary in the packaging of many materials, such as for example, explosives, food products, liquids and paste and hygroscopic materials to provide a waterproof container, to prevent moisture from contaminating the contents of the package or to prevent the loss of solvent from the packaged material. In these instances a container is generally provided which is sealed or otherwise closed in such a manner that moisture may not enter the otherwise waterproof container. In the past the closure provided for such containers has been achieved by heat sealing or cementing together the open portion of the container material. In some instances, however, it may not be possible or desirable to use heat sealing because of possible damage to the contents. In other instances the possibility or danger of fire or explosion, as for example, when the contents of the containers are explosives, prevents the use of heat sealing as a method of providing for a water-tight seal. In still other instances the lack of a suitable adhesive or cement has prevented utilization of this method of providing a water-tight closure.

It is therefore an object of the present invention to provide a container closure and to provide a method of sealing a container which will provide a final package which is impervious to water pressure for prolonged periods of time.

According to the present invention the method of providing a container which will withstand considerable hydrostatic pressure comprises gathering the end portions of a waterproof material into a neck, placing a malleable metallic ring snugly about the gathered neck and applying sufficient external pressure distributed about the surface of the ring to eifectively forge together the ring and the neck of waterproof material into substantially a solid having an elliptical cross section. During the application of the above referred to external pressure, the ring is peripherally confined and at the same time substantially reduced. The inner surface of the ring remains smooth and uninfiected with the resultant compressed zone being approximataely elliptical in horizontal cross section.

In the practice of the present invention the dies utilized in compressing or crimping the closure ring about the gathered neck portion of the waterproof material are of such length and design that longitudinal extrusion of the ring is permitted at the same time that the periphery and horizontal cross section of the ring is reduced. In some instances the longitudinal extrusion of the ring takes place entirely within the confines of the dies. It may however also be desirable to utilize dies which are approximately equal in length to the original length of the ring. In this case the compression deforms the metal ring within the confines of the die and permits the longitudinal extrusion of the metal beyond the ends of the die face thus forming a flare or bead and a smoothly rounded lip. The formation of beads at both ends of the ring eliminates any tendency of the closure to break the waterproof material during afiixation of the ring to the waterproof material 3,011,690 Patented Dec. 5, 1961 particularly if during compression of the ring areas of sharply localized fatigue develop.

The flexible waterproof material from which containers of the present invention may be fabricated include rubber, polyethylene, polytetrafluoro ethylene, polyvinyl chloride, polyethylene terephthalate and similar polymers and inner polymers in the form of water impervious films.

It is also within the scope of the present invention to employ the above referred to water impervious films in the form of sheets, tubes or bags in combination with the hereinafter more fully described closure ring. If tubular material is employed it will of course be necessary to utilize two closure rings to provide a container which is sealed at both ends.

Having now indicated generally the nature and purpose of the present invention, the advantages and improvements in the container closure and the method for providing a water-tight seal to a water impervious film will be apparent from the following more detailed description taken in connection :with the accompanying drawings wherein: 7

FIGURE 1 is an end section of a closure ring of the present invention.

FIGURE 2 is a horizontal section of the ring shown in FIGURE 1.

FIGURE 3 is an end view in vertical transverse section of the ring of FIGURE 1 about the gathered neck of a waterproof material and placed in position in the crimping dies.

FIGURE 4 is a vertical transversev section similar to FIGURE 3 showing the ring about the neck of waterproof material in its compressed form within the die assembly.

FIGURE 5 is an isometric view of the ring of FIGURE 4 fastened to a waterproof bag. 1

FIGURE 6 is a side view showing a waterproof bag with the closure of the present invention securely fastened thereto.

FIGURE 7 is a side view showing a waterproof bag and an alternate embodiment of a ring closure of the present invention.

In the preferred manner of carrying out the present invention the bag 1 of FIGURE 6 is filled with explosive material and the open end portion of the bag is gathered into a neck portion 2. A malleable metallic ring 3, as shown in FIGURE 1 and adapted to fit snugly about the gathered neck is placed about the neck portion of the bag and the assembly is placed between the upper and lower jaws 6 and 7, of a crimping die as shown in FIGURE 3. The jaws 6 and 7, are then pressed together as shown in FIGURE 4 so that the ring 3, is diminished in periphery and tightly grips neck 2, of bag 1, in a smooth uninfiected curve. The crimping jaws 6 and 7, are brought together as shown in FIGURE 4 and external pressure is brought to bear on the ring closure, the pressure being distributed about the surface of the ring to etfectively forge together the ring and neck of the bag into substantially a solid having an elliptical cross section. During the application of the pressure on the ring surface the ring is peripherally confined between the jaws so that the periphery of the ring is substantially reduced and the horizontal cross section of the ring and bag neck is also reduced. It is noted that after compression of the ring on the bag neck as shown in FIGURE 4 the inner surface of the ring remains smooth and unin-flected and the resultant compression zone is approximately elliptical in horizontal cross section. In some instances it may be desirable to permit longitudinal extrusion of the ring beyond the ends of the die in order to form a flare or head as shown at 5 of FIGURE 7. This longitudinal extrusion of the ring beyond the ends of the die eliminates any tendency of the ring closure either during the compression of the ring on the bag neck or during subsequent handling. of the bag material to pierce or break the bag material.

The malleable metallic ring of the present invention may be fabricated from any suitable metal, such as for example, brass, copper, aluminum, steel, etc., having sufficient form persistence after being compressed into seal a ing relation to the bag, FIGURE 4, to retain its ultimate compressive. force on the bag. The metal must also have sufiicie'nt. ductility to flow the required amount without.

strain hardening to the extent that breakage occurs. The thickness of the metal ring will depend on. the material from which the bag is fabricated which in turn is dictated by the service. required; however, the metal ring thickness must be heavy enough to prevent buckling during the crimping operation. By way of illustration it. has been found. desirable .to use aluminum rings of from 7 1;" to about A" long having an outside diameter of from 0.625" to about 0.775" and an inside diameter of from about 0.561." to about.0.584" on 6 ml. in thickness polyethylene bags. of from. 4 /1" to about 6" in diameter.

It is desirable in many instances to provide a radius orvbeveled surface. 4 as shown in FIGURE 2 on. the inner surface of the metal ring to prevent damage to the. bag material by the edge of the fastener during the. crimping operation or during subsequent. handling of the. packaged material where a sharpened or rough surface may eventually x'vearor cut through the bag material. It is therefore found desirable to provide a radius of from about 0.020" to about. 0.062" to. the inside edge of the metal ringin order to. insure against damage to the polyethylene- The ring closures and method of the present. invention.

in which the ringis confined and subjected to pressure distributed about its periphery results in a, closure which avoids pockets and permits. variable. pressures of, from about 10,000. poundsto about.25,000 pounds to be applied to the ring surface Without puncturing the bag or buckling the ring.v A pressure of. about. 18,000 pounds was found eifective in closing a 0.772." outside diameter by 0.580"

inside diameter long copper ring used as a closure for a 6 ml. in thickness polyethylene bag 6" in diameter containing nitrocarbonitrate explosive. The bag of nitrocarbonitrate was submerged under 40' of water for 24 hours. The contents and the. bag were examined after the 24 hour period and no evidence of water leakage was noted.

While a particular embodiment of the present invention has been illustrated and described herein, it is not intended to limit the invention to such a disclosure and changes and modifications may be incorporated and embodied therein within. the scope ofthe following claim.

I claim:

A closed containerhaving explosive material therein, said container being fabricated of flexible waterproof material and impervious to water pressure for prolonged periods of time. comprising a gathered end portion of saidv flexible material, a ring of malleable metal crimped about.

said gathered end portion said ring having a smooth continuous and uninflected internal surface and said embraced zone being substantially solid and approximately elliptical in horizontal cross section.

References. tilted. in the file of this patent UNITED STATES PATENTS 

